Vitamin B.sub.12 has been prepared synthetically but the process is prohibitively expensive.
In U.S. Pat. No. 2,703,302, it is disclosed that vitamin B.sub.12 -active substances may be produced by fermentation utilizing selected vitamin B.sub.12 -active substance producing strains of microorganisms of the genus Alcaligenes, the genus Bacillus, the genus Escherichia, the genus Mycobacterium, the genus Pseudomonas and the genus Streptomyces.
An improved fermentation process for the preparation of substances having vitamin B.sub.12 -activity by fermentation using Pseudomonas denitrificans is disclosed in U.S. Pat. No. 3,018,225. The process is said to produce vitamin B.sub.12 -active substances in high yield at a rapid rate and without the significant production of undesirables such as antibiotics.
The currently employed commercial process for producing vitamin B.sub.12 by fermentation on carbohydrate media employs highly selected strains of microorganisms such as Proionobacterium shermanii or Streptomyces species. Obviously, it would be advantageous to be able to produce vitamin B.sub.12 commercially employing less expensive non-carbohydrate media.